DRAGONFLIES AND DAMSEI^I^UES IN PONDFISH CUI.TURE. 237 



at the bank (Illinois River) deposited for me in a watch glass of water in a few min- 

 utes' time about 5,200 eggs. This number is an estimate from a partial count" (p. 75). 



The present author stood in one spot on the bank of pond 4D and captured within 

 half an hour six L. luctuosa females as they came to the pond to oviposit and from them 

 fully 4,000 eggs were obtained. 



For stocking purposes the eggs of the different species do not need to be kept 

 separate. On another afternoon females of L. luctuosa^ Erythemis, and Leucorrhinia 

 were allowed to deposit their eggs in the same tumbler and all hatched out together 

 without apparent trouble. 



Armed then with an insect net and a convenient receptacle, thousands of eggs can be 

 easily obtained in a short time at any place where the dragonflies are ovipositing and 

 only the eggs of desirable species need be taken. These eggs can then be carried to 

 the pond and placed loosely upon the bottom or on the floating algae, care being taken 

 that they do not get buried in silt or mud, but remain on the surface; or they can be 

 kept in the original receptacle until they hatch, and then the nymphs can be turned 

 loose in the pond, not all in one place, but well distributed. The number of nymphs 

 obtained in this way need only be limited by the patience of the collector. 



If the eggs are allowed to hatch before being placed in the fishpond, care should be 

 taken that they do not require a long transportation. Mrs. Aaron gave this warning: 

 ''The question of transporting the young larvae from the breeding tanks to the mosquito- 

 infested ponds is to be considered. Although they are tough and can stand jolting, 

 only a few can be carried in one receptacle. Twenty put in one jar would be found 

 to be an inextricable, kicking mass of cannibals after a mile's transportation" (lyam- 

 born, 1890, p. 63). While perhaps transportation for a mile would produce this 

 result, no difficulty has been experienced in carrying thousands of newly hatched 

 nymphs from the laboratory to the fishponds, a distance of 500 yards. 



Anax, ^schna, and the damselflies insert their eggs by means of an ovipositor into 

 living or dead vegetable tissue either beneath the water or resting upon its surface. 

 The females of these species can be watched while ovipositing and after they have 

 finished the leaves or stems containing the eggs can be removed and transferred to the 

 fishpond or they may be kept in water until they hatch. These females will not deposit 

 eggs in a tumbler or basin, like those previously mentioned, but just as many can be 

 secured by gathering the vegetation containing them. 



Sufficient experience might enable one to distinguish between the eggs of different 

 species, but ordinarily the vegetation must be transferred to the fishpond with all the 

 eggs it may happen to contain. It is surprising, however, to find how often it proves 

 that practically all the eggs in a single leaf or stem are those of one species. 



Females of Enallagma hageni were observed inserting their eggs in the tissue of 

 crex-grass leaves that had fallen into the water. Five of these leaves that contained 

 fully 1,500 eggs were obtained, and these were cut into short lengths and kept in tum- 

 blers of water until the eggs hatched. Similarly, Argia moesta putrida was observed 

 descending a small water-soaked branch of willow near one of the wing dams in the 

 Mississippi River in order to deposit its eggs, the female dragging the male down with 

 her during the process. On pulling the branch out of the water a dozen couples of 

 this damselfly flew off from it at varying depths, and the softened wood was found 

 to be literally filled with eggs for a distance of 2 feet. A partial count and an estimate 



